Photographic elements and processes lithographic silver halide element containing a 1-(amidophenyl)-5-mercaptotetrazole sensitizing agent and development process of using same

ABSTRACT

High contrast photographic elements comprising a support coated with a silver halide emulsion wherein the halide comprises at least about 50 mole percent chloride and containing a 1(amidophenyl)-5-mercaptotetrazole, provide improved speed control without undesired change in sensitometric characteristics. Methods for processing such elements in a continuous transport processing machine are also described.

United States Patent [191 Salesin 1 Jan. 2, 1973 [541 PHOTOGRAPHICELEMENTS AND PROCESSES LITHOGRAPHIC SILVER HALIDE ELEMENT CONTAINING Al- (AMIDOPHENYL)-5- MERCAPTOTETRAZOLE SENSITIZING AGENT AND DEVELOPMENTPROCESS OF USING SAME [75] Inventor: Eugene D. Salesin, Rochester, N.Y.

[73] Assignee: Eastman Kodak Company,

Rochester, N.Y.

[22] Filed: Jan. 12, 1971 [2]] App]. No.: 105,993

Related U.S. Application Data [63] Continuation-in-part of Ser. No.754,967, Aug. 23,

1968, abandoned.

[52] US. Cl. ..96/107, 96/109, 96/95, 96/76 R, 96/66 R, 96/33 [5 l] Int.Cl. ..G03c 5/24, G030 l/28, G03c 5/30 [58] Field of Search....96/l07,65, 33, 109, 66, 76 R, 96/95 Primary Examiner-J. Travis Brown AssistantExaminer-Won H. Louie, Jr. Attorney-Robert W. Hampton, Bernard D. Wieseand Myron B. Kurtzman [5 7 ABSTRACT High contrast photographic elementscomprising a support coated with a silver halide emulsion wherein thehalide comprises at least about 50 mole percent chloride and containinga l-(amidophenyl)-5-mercaptotetrazole, provide improved speed controlwithout undesired change in sensitometric characteristics. Methods forprocessing such elements in a continuous transport processing machineare also described.

11 Claims, No Drawings PHOTOGRAPHIC ELEMENTS AND PROCESSES LITHOGRAPHICSILVER I-IALIDE ELEMENT CONTAINING A l-(AMlDOPHENYL)-S-MERCAPTOTETRAZOLE SENSITIZING AGENT AND DEVELOPMENT PROCESS OF USINGSAME The application is a continuation-in-part of Ser. No. 754,967 filedAug. 23, 1968, by Eugene D. Salesin, now abandoned.

BACKGROUND OF THE INVENTION 1. Field ofthe lnvention This inventionrelates to photographic materials, their preparation and use. One aspectof the invention relates to a continuous process for processing exposedhigh contrast photographic elements in a continuous transport processingmachine employing photographic elements containing al-(amidophenyl)--mercaptotetrazole. Another aspect of the inventionrelates to photographic emulsions containing such a l-(amidophenyl)-5-rnercaptotetrazole, which results in desired restrainingof development upon processing without undesired change in dot quality,contrast or fog of high contrast images.

2. Description of the Prior Art ln the graphic arts field, where it isdesired to make photographic line and halftone reproductions, it iscustomary to employ emulsions providing extremely high contrast images.During development, the developed areas grow autocatalytically at a veryhigh developing rate to produce extremely high contrast which isnecessary for half-tone patterns and other such images requiring highdot quality. Developers utilized with lith type photographic films arequite different in composition from typical black-and-white filmdevelopers. ln order to obtain very high contrast and sharp halftonedots, it has been the practice to formulate developers for such filmsfrom essentially hydroquinone, an alkaline development activator, alkalimetal bromide and a low level of sulfite ion. The low level of sulfiteion partially stabilizes the developer solution for a short period oftime and is achieved in all present commercial developers of this typeby use of sodium formaldehyde bisulfite, which acts as a sulfite ionbuffer.

Such developer solutions for high contrast lith films presently used incontinuous transport processing machines have a number of disadvantages.The photographic quality obtained with a given film is usually inferiorto that obtained in careful tray processing. The sensitivity of highcontrast films to developer exhaustion products and development ingeneral as well as variations in local developing agent concentrationmakes these films vulnerable to localized changes in sensitometricproperties. For example, the dots in a high contrast film can bedistorted and exhibit size changes depending on the orientation anddirection of travel through the machine processor. This undesirable dotdistortion is manifested in changes in the H and D curve of highcontrast films which are processed in con tinuous transport processingmachines. 1

Problems in the graphic arts field have also been. encountered withregard to speed loss where materials are incorporated in a photographicelement in an effort to improve dot quality. For example, it has beenattempted in the past to incorporate l-phenyl-S-mercaptotetrazole incoatings for photographic elements in order to improve dot quality. Suchcoatings have not proved satisfactory because an undesirable speed lossis produced which is believed to be a result of the leaching of1-phenyl-5-mercaptotetrazole out from the coatings. The leached outl-phenyl-S-mercaptotetrazole present in the developer solution wouldchange the s ensitometric properties of subsequently processed coatings.This is due to the fact that in a processing machine phenylmercaptotetrazole gradually builds up in concentration until the entirebath must be replaced or addendum must be added to account for increasedphenyl mercaptotetrazole concentrations. Accordingly, it is desirable toprovide a material which satisfactorily controls speed in processingwithout changing any of the desired sensitometric characteristics of thecoatings during machine processing.

The use of l-phenyl-5-mercaptotetrazole in a photographic emulsion iswell known as described, for example, in U.S. Pat. No. 2,403,927 ofKendall et'al. issued in 1946. The use of related compounds is alsoknown, such as described in U.S. Pat. No. 3,266,897 of Kennard et al.issued Aug. 16, 1966, and U.S. Pat. No.

3,295,976 of Abbott and Salminen issued Jan. 3, 1967..

U.S. Pat. No. 3,295,976 of Abbott and Salminen issued Jan. 3, 1967,describes the method of selectively controlling over-development of amulti-layer photo graphic element by a negative developer in a hightemperature color process by negative development of this element in thepresence of a l-(amidophenyl)-5-mercaptotetrazole. There is nodisclosure in these patents, however, of the high contrast elementshaving the particular silver halide emulsions employed in the graphicarts. Moreover there is no disclosure in this patent of use ofl-(amidophenyl)-5 mercaptotetrazole in a high contrast photographicelement.

It is also known to use l-(amidophenyl)-5-mercaptotetrazoles asantifoggants in photographic silver halide emulsions which have foggedinternal image silver halide grains and unfogged surface latent imagesilver halide grains as disclosed in French Pat. No. 1,492,] 32 ofKodak. This emulsion, however, has not been employed in high contrastphotographic elements utilized in the graphic arts for producing lineand halftone dot reproductions.

Accordingly, there is a need for a high contrast photographic elementand process which avoids the problems resulting from leaching out ofl-phenyl-S- mercaptotetrazole in continuous transport processingmachines.

An object of the invention accordingly is to provide a high contrastphotographic element containing a lphenyl-S-mercaptotetrazole compoundwhich does not significantly diffuse into processing solutions duringmachine processing thereby causing undesired sensitometric properties.

Another object is to provide a high contrast photographic emulsion,suitable for use in the graphic arts, which contains a non-diffusingl-phenyl-5-mercaptotetrazole compound.

A further object is to provide a process, especially a continuoustransport process, which is suitable for developing an image in a highcontrast photographic element as described.

SUMMARY or THE INVENTION graphic emulsion. In another embodiment thereis provided a high contrast photographic emulsion containing al-(amidophenyl)-5-mercaptotetrazole. In yet another embodiment, acontinuous process is provided for processing a lith element in onecontinuous motion by transporting it into, through and out of at leastone processing solution in the manner shown, for example, in U.S. Pat.No. 3,025,779 of Russell and Kunz issued Mar. 20, i962; U.S. Pat. No.3,078,024 of Sardeson issued Feb. 19, I963; U.S. Pat. No. 3,l22,086 ofFitch issued Feb. 25, i964; U.S. Pat. No. 3,149,551 ofCramer issuedSept, 22, .1964; U.S. Pat. No. 3,l56,l73 of Meyer issued Nov. 10, l963;and U.S. Pat. No. 3,224,356 of Fleisher and Hixon issued Feb. 21, 1965;wherein said element is developed in a liquid developer comprising asilver halide developingagent and a carbonyl bisultite-aminecondensation product. Such an element and process provides improvedspeed. control without undesired change of sensitometriccharacteristics.

DESCRIPTION OFYTHE PREFERRED EMBODIMENTS undesired change ofsensitometric characteristics is suitable according to the invention. Anespecially preferred group of mercaptotetrazoles are the l-(amidophenyl)-5-mercaptotetrazole represented by the formula: v

NHX

methylphenyl and butylphenyl and aralkyl, such as tolyl and xylyl; Thehydrocarbon radical can contain various substituent groups such asalkoxy, e.g., containing one to five carbon atoms such as methoxy,ethoxy, propoxy, butoxy and pentoxy, phenoxy, halogen, cyano, nitro,

amino, sulfo, sulfamyl, substituted sulfamyl, sulfonylphenyl,sulfonylalkyl, sulfonamidoalkyl, ,sul-

fonamidophenyl, carboxylic acid, carboxylate, carbamyl, carbamylphenyl,carbamylalkyl, carbonylalkyl, carbonylphenyl and similar groups.

Suitable 'l-(amidophenyl) 5-mercaptotetrazoles include:

l-( 3-caproamidopheny! )-5-mercaptotetrazole, l-( 3-pelargonamidophenyl)-5-mercaptotetrazole,

l-[3-(alpha-2,4 di-t-amylphenoxy)acetamidophenyll-S-mercaptotetrazole,l-( 3-methylsulfonainidophenyl )-5-mercaptotetrazole, l-( 3-ptoluenesulfonamidophenyl )-5-mercaptotetrazole, and l-(3-acetamidophenyl )5-mercaptotetrazole. l-(amidophenyl)-5-rnercaptotetrazoles employed according to the invention can beprepared by methods known in the art such as, for example, by reactionof a corresponding I l-(aminophenyl)-5 mercaptotetrazole hydrochloridewith an acid chloride of the desired amido compound. This is disclosed,for example, in U.S. Pat. No. 3,295,976 of Abbott and Salminen issuedJan. 3, I967.

The concentration of l-(amidophenyl)-5-mercaptotetrazole which issuitable for providing desired dot quality without. loss in speed orother desired sensitometric properties, is subject to wide variation. Ina photographic emulsion layer or a layer contiguous thereto, al-(amidophenyl)-5-mercaptotetrazole concentration of about 5 to about275 milligrams, e.g., about l0 to about 250 milligrams per mole ofsilver present is suitable.

Any suitable method can be employed for incorporating the describedmercaptotetrazole compounds in a photographic emulsion or layercontiguousthereto, such as mixing the described compound in a coatingcomposition prior to the coating on a support/Any method and/or meanscommonly employed for incorporating addenda into photographic layers canbe employed according to the invention.

The developing agents,which can be employed in processing the describedphotographic elements of the invention can be any of those commonlyemployedin. the graphic arts. Useful silver halide developing agents,forexample, include the dihydroxy benzenes such as hydroquinone;chlorohydroquinone; bromohydroquinone; 2,3-dichlorohydroquinone;2,5-dimethylhydroquinone; 2,3-dibromohydroquinone; 1,4-dihydroxy-2-acetophenone-2,S-dimethylhydroquinone; hydroquinone;2,5-dibenzoylaminohydroquinone; 2,5- diacetaminohydroquinone; etc.Esters of such compounds, -for example, formates and acetates, can alsobe employed. These developing agents can be used alone or in anycombination and can be employed in any concentration which is effectivefor development.

A suitable concentration for the developing agent is about 0.05 to about0.50 mole per liter of developer composition and is typically from 0.10vto about 0.30 mole per liter of developer composition.

Development activators, typically alkaline activators, are employed inthe developer composition employed for processing elements of theinvention. These include any of the inorganic and/or organic alkahesemployed in photographic processing solutions, such as alkali metalcarbonates and hydroxides, for example,

2,5-diethylhydroquinone; I 2,5 -di-p-phenethylsodium hydroxide, lithiumhydroxide, and potassium hydroxide, sodium carbonate, and potassiumcarbonate. Inorganic alkaline activators can also be employed, such asamino alkanols, for example, amino propanol, amino ethanol,diethylamine, triethylamine, iminodiethanol, etc. Any suitableconcentration of development activator can be employed which providesthe desired image based on the described photographic element. Aconcentration is employed which typically provides a developercomposition having a pH well above 7, such as about 9 to about 13.

The developer compositions employed for processing the describedphotographic elements can also contain carbonyl bisulflte-aminecondensation products, preferably formaldehyde bisulfite-aminecondensation products, such as sodium-2-hydroxyethylaminoethanesulfonate; sodium-2-hydroxypropylaminomethane sulfonate;sodium-1,1-dimethyl- 2-hydroxyethylaminomethane sulfonate; sodium-1,1-bis-(hydroxymethyl)ethylaminomethane sulfonate;sodium-tris(hydroxymethyl)methylaminomethane sulfonate;sodium-3-hydroxypropylaminomethane sulfonate;sodium-bis(2-hydroxyethyl)aminomethane sulfonate; sodium-N,N-bis[2-(l-hydroxy)propyl]aminomethane sulfonate; sodium-N- isopropyl-N-(2-hydroxyethyl)-aminomethane sulfonate;sodium-N-ethyl-N-(2-hydroxyethyl)- aminomethane sulfonate; andsodium-N-methyl-N-(Z- hydroxyethyl)-aminomethane sulfonate. The carbonylbisulfiteamine condensation products can be used alone or in acombination and can be employed in any concentration which is effectiveto provide a low level of sulfite ion in the developer composition. Asuitable concentration for the carbonyl bisulfiteamine condensationproduct is about 0.1 to about 1.0 mole per liter of liquid developercomposition and is preferably about 0.25 to about 0.50 mole per liter ofliquid developer composition.

The high contrast photographic elements described according to theinvention comprise a support bearing a photographic silver halideemulsion layer in which the halide comprises at least about 50 molepercent chloride. The photographic emulsions employed ac cording to theinvention are lith emulsions. Such emulsions develop to very highcontrast when developed in an infectious developer. (See J.A.C. YuleFormaldehyde-Hydroquinone Developers and Infectious Development, Jour.of the Frank. lnst., Vol. 239, No. 3, March, 1945.) A lith emulsion istypically a high contrast photographic silver halide emulsion in whichthe halide comprises at least 50 mole percent chloride and less than 5mole iodide, the remainder being bro mide, said emulsion when exposed ona sensitometer and developed for 2 minutes in Kodak D-85 Developer at C.having a gamma of at least 4 measured between a density of 0.3 and 3.0.

Preferably the halide in the described photographic silver halideemulsion comprises a higher concentration than about 50 percentchloride, such as at least about 85 mole percent chloride and typicallyat least about 90 mole percent chloride, the balance, if any, being, forexample, bromide. These emulsions when exposed on a sensitometer andprocessed in 1 9'4 minutes through an amine developer system such asdescribed in copending application Ser. No. 661,532, entitled,

Photographic Developer Composition Containing Carbonyl Bisulfite AmineCondensation Product and Free Amine", filed Aug. 18, 1967 now U.S. Pat.No. 3,573,914, will have a contrast of at least about 6. Such preferredemulsions provide particularly good results in high contrastphotographic elements and good dot quality. The halide of thephotographic silver halide emulsion can also contain a small amount ofiodide such as less than about 5 mole percent than is desired. Silverhalide emulsions in which the halide comprises 100 mole percent chloridehave also been found to be useful.

Other photographic elements containing lith emulsions comprising about85 mole percent silver chloride are described in: Henn and Goffe, U.S.Pat. No. 3,030,209, issued Apr. 17, 1962, copending U.S. applicationSer. No. 661,530 of Salesin entitled High-Contrast Photographic Elementsand Methods for Processing Same, filed Aug. 18, 1967, and copending U.S.application Ser. No. 66l,53l of Milton, entitled High-ContrastPhotographic Elements and Methods for Processing Same (Case A), filedAug. l8, i967 now U.S. Pat. No. 3,600,174.

The photographic silver halide emulsion layers of the high contrastphotographic elements described according to the invention and/or layerscontiguous thereto can contain any of the commonly employed hydrophilicwater-permeable binding materials suitable for this purpose. Suitablematerials include, for example, gelatin, colloidal albumin, polyvinylcompounds, cellulose derivatives, acrylamide polymers, etc. Mixtures ofsuch binding agents can also be used. The binding agents for thedescribed layers of the high contrast photographic elements of theinvention can also contain dispersed polymerized vinyl compounds,especially those which increase the dimensional stability ofphotographic materials. Suitable synthetic polymers of this typeinclude, for example, water-insoluble of alkyl acrylates andmethacrylates or acrylic acid. Such compounds are described for example,in U.S. Pat. No. 3,142,568 of Nottorf, issued July 28, 1964; U.S. Pat.No. 3,193,386 of White, issued July 6, 1965', U.S. Pat. No. 3,062,674 ofHouck, Smith and Yudelson, issued Nov. 6, 1962, and U.S. Pat. No.3,220,844 of Houck, Smith and Yudelson, issued Nov. 30, 1965. Thesecompounds can also be incorporated into a separate layer of thephotographic element. The vinyl polymers are generally employed inconcentrations in the range of about 20 to about percent by weight, andmost often in concentrations of at least 50 percent by weight, based onthe weight of the binding agent.

The described high contrast photographic elements of the invention cancontain an overcoat layer, such as a heavy overcoat comprising awater-permeable colloid. While any of the hydrophilic water-permeablebinding materials described for the emulsion and/or other layers of thehigh contrast photographic element can be used in the overcoat layer,gelatin has been found to produce good results. lf desired the overcoatlayer can also contain dispersed polymerized vinyl compounds asdescribed.

The described high contrast photographic elements of the invention cancontain a photographic halide silver emulsion coated on a wide varietyof supports. Hydrophilic colloid layers can be coated on one or bothsides of the support if desired. Typical supports include any of thosecommonly employed in preparing photographic elements for the graphicarts field such as cellulose nitrate film, cellulose ester film,polyvinyl acetal film, polystyrene film, poly(ethylene terephthalate)film and related films and/or resinous supports. Glass, paper and metalsupports can also be used. Supports such as paper, which are coated withan alpha-olefin polymer, particularly polymers of alpha-olefinscontaining two or more carbon atoms, such as polyethylene,polypropylene, ethylene-butene copolymers and the like are suitable.

The photographic silver halide emulsions of the high contrastphotographic elements of the invention can be sensitized using any ofthe well known techniques employed in photographic emulsion production,for example by digesting with naturally active gelatin or varioussulfur, selenium, tellurium compounds and/or gold compounds. Theemulsions can be sensitized with salts of noble metals of Group VIII ofthe Periodic Table which have an atomic weight greater than 100.

The photographic emulsions of the invention can also contain otheraddenda commonly employed in photographic elements used in the graphicarts such as speed increasing addenda and/or addenda for increasingcontrast such as quaternary ammonium salts, polyethylene glycols,thioether sensitizers or combinations thereof. It can also containcoating aids such as anionic, nonionic and amphoteric surface activeagents and the like. They also contain gelatin plasticizers,antifoggants including organic and inorganic antifoggants as well ashardeners such as aldehyde hardeners including, for example,formaldehyde, mucochloric acid, glutaraldehyde bis(sodium bisulfite),maleic dialdehyde, aziridines, dioxane derivatives andoxpolysaccharides.

The high contrast photographic silver halide emulsions of the inventioncan be ortho-sensitized or pansensitized with spectral sensitizing dyes.For instance, these emulsions can be spectrally sensitized withmerocyanine dyes, hemicyanine dyes and/or dyes useful in sensitizingsuch emulsions are described for example in U.S. Pat. No. 2,526,632 ofBrooker and White, issued Oct. 25, 1950; and U.S. Pat. No. 2,503,776 ofSprague, issued Apr. 11, I950.

Photographic elements according to the invention can be processedemploying processing solutions and methods employed in the graphic artsand especially those employed for processing lith emulsions. They arepreferably processed, typically after exposure through a contact screenemployed in the graphic arts, using a 90 second development time in aKodalith Roller Transparent 324 Film Processor of the type described inU.S. Pat. No. 3,025,779 of Russell and Kunz, issued Mar. 20, 1962,employing typically a developer having the following composition:

Sodium-bis-( 2-hydroxyethyl)- aminomethane sulfonate" 82.0 grams Sodiumsulfite 30.0 grams Boric acid 7.5 grams I-Iydroquinone 22.5 gramsPotassium bromide 1.6 grams 2,2'-Iminodiethanol 39.0 grams Water to make1 liter pH 9.5

Accordingly, another embodiment of the invention comprises in acontinuous process for processing an exposed high contrast photographicelement comprising a 7,

support coated with a photographic silver halide emulsion wherein saidelement is processed in one continuous motion by transporting it into,through and out of at least one processing solution, the improvementcomprising the combination of:

a. developing said element in a liquid developer composition comprisinga silver halide developing agent and a carbonyl bisulfite-aminecondensation product,

b. said halide comprises at least about 50 mole percent chloride, andpreferably at least mole percent chloride, and

c. said element has a coating containing a l-phenyl- S-mercaptotetrazolecompound having the property of being non-diffusible in a photographicemulsion. Such a process wherein the l-phenyl-5-mercaptotetrazolecompound is a l-(amidophenyl)-5-mercaptotetrazole, as described, ispreferred. A process of the invention is also preferred wherein thedeveloper solution is an aqueous solution containing a hydroquinonedeveloping agent in a concentration of about 0.05 to about 0.50 mole perliter of solution and containing a formaldehyde bisulfite-aminecondensation product present in a concentration of about 0.10 to about1.0 mole per liter of developer solution.

Typically the processed element of the invention, as employed in thegraphic arts field, consists of a pattern of dots, areas commonlyreferred to as shadow dots and areas known as high-light areas.Intermediate between the two extremes of areas referred to as shadowdots and areas known as high-light areas are areas of varying size. Thecommon method in the graphic arts for measuring the quality ofreproduction of a photographic element is to examine the dot areas. Thequality of dot can be expressed on any convenient scale, but for thepurposes of the invention the following scale can be employed to referto a quality of dot: a grade scale between 1 and 9 is employed wherein 9is excellent and l is extremely poor with varying degrees of qualitybetween these two points. This scale is employed herein to designate thequality ofimage.

The following examples are included for a further understanding of theinvention.

EXAMPLEI A fine-grain silver chlorobromoiodide gelatino emulsioncontaining mole percent chloride, 9 mole per cent bromide and 1 molepercent chloride is chemically sensitized with sulfur and gold compoundsand coated on a polyethylene terephthalate support. The emulsion isapplied to the support at the rate of 456 milligrams of silver persquare foot, 296 milligrams of gelatin per square foot and 296milligrams per square foot of alkyl acrylate polymer as described inU.S. application Ser. No. 525,272 filed Dec. 20, 1965 of D. A. Smith nowU.S. Pat. No. 3,459,798. A gelatin overcoat is coated on the resultingemulsion layer at 82.6 milligrams per square foot. The resulting productis designated as Product A and employed as a control.

Identical coatings are made with the exception that l-(3-acetamidophenyl )-5-mercaptote trazole also known as AcPMT, is addedto separate portions of the described emulsion at the rate respectivelyof 5, 25 and 125 milligrams ofl-(3-acetamidophenyl)-5-mercaptotetrazole-per mole of silver present.These products mercaptotetrazole in place of l-(3-acetamidophenyl)-5-mercaptotetrazole per mole of silver.

are designated, respectively, as Product B, Product C G. Product Gcontains 125 milligrams of l-(3- and Product D.acetamidophenyl)--mercaptotetrazole per mole of The resulting driedcoatings are exposed using tung- 5 silver. sten illumination to a stepwedge through a magenta H. Product H contains 250 milligrams of 1-(3-contact screen. The element are then processed using aacetamidophenyl)-5-mercaptotetrazole per mole of 90 second developmenttime in a Kodalith Roller ilvr- Transport 324 Film Processor asdescribed in 11.5. Pat. 500 milliliter portions of the developersolution No. 3,025,799 of Russell and Kunz, issued Mar. 20, described inExample 1 are employed. Fifteen unex- 1962 employing the followingdeveloper: posed 4 X inch sheets (4.15 square feet) of each of thedescribed Products E, F, G and H are passed d H y y y through thedescribed developer portions. The result- Sulfonatei 23:8 22:: ingdeveloper is designated as Developer A. Then 30 Boric acid 7.5 gramsunexposed 4 X 10 inch sheets (8.30 square feet) of gydmfiuinone gramsProducts E, F, G, and H are passed through separate otassrum bromide 1.6grams zyzniminodiethanoi 300 grams 500 milliliter portions of thedeveloper composition set J" make out in Example 1. The resultingdeveloper is designated Sodiu in formaldehyde bisulfite and 2,2'-iminodiethanol can be used as Developer B" to form thiscompound insitu.A control, as described in Example 1, containing neitherphenylmercaptotetrazole or l-( 3- The resulting image consists of apattern of dot areas acetamidophehyll's'mercapwtetrazole is Preparedcommonly referred to in the art as shadow dots and and exposed as Setout in Example The resulting areas known as high-light areas.Intermediate between 25 is Processed for l 84 minutes w Seconds, atthese two extremes are areas of varying size including a 2700 in each ofthe resulting developer Solutions, so-called middletone area. Theletters H, M and S each of Developer A and Developer The results ofdescribed herein refer respectively to high-light, these tests are Q Pto the Control Processed in a iddl d h d 1 w fresh developing solutionwhose speed is assigned 100. The results obtained are et out i Table l,Th l The results are also compared to the control processed tive speed,effective contrast and dot quality are given in a fr sh d velopingSolution to which is added 8.72 for varying development time.Development time is milligrams of l-(3-acetamidophenyl)-5-mercapvariedbetween l /2 minutes, i.e. 90 seconds, and 2 totetrazole per 500milliliters of developing solution. minutes, i.e., 135 seconds. (8.72milligrams of l-(3-acetamidophenyl)-5-mercap- TABLE 1 Dot quality AcPMTRelative speed Effective contrast rngJAg 1% 1 4' Product mole 1% 1% 2 2%1% 1% 2 2% M HMS M M A (control) None 100 141 155 166-' 7.7 8.5 9.0 0.07 484 8 8 B 5 100 132 138 149 7.7 8.8 9.0 0.0 8 484 8 EXAMPLE 2 This isa comparative example illustrating advantages of the invention.

Four photographic elements are prepared as set out in Example 1 and aredesignated respectively as Products E, F, G, and H. These productscontain the following differences from the products described in Example1:

E. Product E contains no l-( 3-acetarnidophenyl)-5- mercaptotetrazole orl-phenyl-5-mercaptotetrazole.

F. Product F contains 125 milligrams of l-phenyl-S- totetrazole iscalculated as the approximate amount that is leached out underequilibrium conditions for processing coatings containing milligrams of1-(3- acetamidophenyl)-5-mercaptotetrazole per mole of silver).

The following Table 11 lists the results obtained. Table II lists therelative speeds of the control coating processed in developing solutionsthrough which were passed the described 4 X 10 inch sheets of ProductsE, F, G and H.

TABLE II prior art invention invention Control Prod. F Prod. G Fred. HProd. E 125 mg. 125 mg. 250 mg. None PMT/mole AcPMT/ AcPMT/ mole moleDeveloper A 102 94 101 96 Developer B 94 53 99 91 The relative speed ofthe control coating when employing a fresh developer containing 8.72milligrams of l-(B-acetamidophenyl)-5-mercaptotetrazole is 76, whereasthe relative speed of a control containing no mercaptotetrazole compoundis 100.

A comparison of the relative speeds of each of the coatings listed inTable II illustrates that:

a. l-( 3-acetamidophenyl)-5-mercaptotetrazole, when added to thedescribed developing solution, provides a speed loss for coatingsprocessed therein;

b. photographic elements according to the invention containingl-(3-acetamidophenyl)-5-mercaptotetrazole provide no speed loss, thusindicating that the described mercaptotetrazole of the invention doesnot leach out of the described coating; and

c. there is a speed loss for the control processed in a developersolution in which coatings containing 1- phenyl--mercaptotetrazole arepreviously processed. This indicates that, surprisingly, by employing aphotographic element of the invention the disadvantageous sensitometriceffects caused by employing a photographic element containingl-phenyl-5-mercaptotetrazole are avoided.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will beunderstood that variationsand modifications can be effected within the spirit and scope of theinvention.

1 claim:

l. A high contrast photographic element comprising a support havingthereon a photographic lith type silver halide emulsion wherein saidhalide comprises at least about 85 mole percent chloride, said elementcontaining a l-(amidophenyl)-5-mercaptotetrazole, said mercaptotetrazolebeing nondiffusible in a photographic emulsion.

2. A high contrast photographic element as in claim 1, wherein saidl-(amidophenyl)-5-mercaptotetrazole compound is present in a coatingcontiguous to said photographic silver halide emulsion.

3. A high contrast photographic element as in claim 1 wherein saidmercaptotetrazole is a l-(3- acetamidophenyl)-5-mercaptotetrazole.

4. A high contrast photographic element as in claim 1 containing about 5to about 250 milligrams of said 1- (amidophenyl)-5-mercaptotetrazole permole of silver present in said photographic silver halide emulsion.

5. A high contrast photographic lith silver halide emulsion, said halidecomprising at least about 85 mole percent chloride, containing about 5to about 250 milligrams of a -(amidophenyl)-l-(aminophenyl)-5-mercaptotetrazole per mole of silver, said mercaptotetrazole beingnondiffusible in a photographic emulsion.

6. A high contrast photographic lith type silver halide emulsion as inclaim 5 wherein said halide comprises I about 90 mole percent chloride,about I mole percent iodide and about 9 mole percent bromide.

7. In a continuous process for processing an exposed high contrastphotographic element comprising a support coated with a photographiclith type silver halide emulsion, said process comprising the steps oftransporting said element in one continuous motion into, through and outof at least one processing solution comprising a liquid developercomposition, the improvement comprising the combination of:

a. said developer composition comprising a silver halide developingagent and a carbonyl bisulfiteamine condensation product,

b. said halide comprising at least about mole percent chloride, and c.said element having a coating containing a l-(amidophenyl)-5-mercaptotetrazole being nondiffusible in a photographicemulsion.

8. A process as in claim 7 wherein said S'mercaptotetrazole isl-(3-acetamidophenyl)-5-mercaptotetrazole.

9. A process as in claim 7 wherein said developing agent is adihydroxybenzene developing agent and said carbonyl bisulfite-aminecondensation product is a formaldehyde bisulfite-amine condensationproduct.

10. The process of claim 7 wherein said developer solution is an aqueoussolution, said developing agent is hydroquinone present in said solutionin a concentration of about 0.05 to about 0.50 mole per liter ofdeveloper solution and said carbonyl bisulfite-amine condensationproduct is a formaldehyde bisulfiteamine condensation product present ina concentration of about 0.10 to about 1.0 mole per liter of developersolution.

11. The process of claim 7 wherein said photographic element istransported by rollers.

2. A high contrast photographic element as in claim 1, wherein said1-(amidophenyl)-5-mercaptotetrazole compound is present in a coatingcontiguous to said photographic silver halide emulsion.
 3. A highcontrast photographic element as in claim 1 wherein saidmercaptotetrazole is a 1-(3-acetamidophenyl)-5-mercaptotetrazole.
 4. Ahigh contrast photographic element as in claim 1 containing about 5 toabout 250 milligrams of said 1-(amidophenyl)-5-mercaptotetrazole pErmole of silver present in said photographic silver halide emulsion.
 5. Ahigh contrast photographic lith silver halide emulsion, said halidecomprising at least about 85 mole percent chloride, containing about 5to about 250 milligrams of a-(amidophenyl)-1-(aminophenyl)-5-mercaptotetrazole per mole of silver,said mercaptotetrazole being nondiffusible in a photographic emulsion.6. A high contrast photographic lith type silver halide emulsion as inclaim 5 wherein said halide comprises about 90 mole percent chloride,about 1 mole percent iodide and about 9 mole percent bromide.
 7. In acontinuous process for processing an exposed high contrast photographicelement comprising a support coated with a photographic lith type silverhalide emulsion, said process comprising the steps of transporting saidelement in one continuous motion into, through and out of at least oneprocessing solution comprising a liquid developer composition, theimprovement comprising the combination of: a. said developer compositioncomprising a silver halide developing agent and a carbonylbisulfite-amine condensation product, b. said halide comprising at leastabout 85 mole percent chloride, and c. said element having a coatingcontaining a 1-(amidophenyl)-5-mercaptotetrazole being nondiffusible ina photographic emulsion.
 8. A process as in claim 7 wherein said5-mercaptotetrazole is 1-(3-acetamidophenyl)-5-mercaptotetrazole.
 9. Aprocess as in claim 7 wherein said developing agent is adihydroxybenzene developing agent and said carbonyl bisulfite-aminecondensation product is a formaldehyde bisulfite-amine condensationproduct.
 10. The process of claim 7 wherein said developer solution isan aqueous solution, said developing agent is hydroquinone present insaid solution in a concentration of about 0.05 to about 0.50 mole perliter of developer solution and said carbonyl bisulfite-aminecondensation product is a formaldehyde bisulfite-amine condensationproduct present in a concentration of about 0.10 to about 1.0 mole perliter of developer solution.
 11. The process of claim 7 wherein saidphotographic element is transported by rollers.